FCK Editor Validation

Here is a good example for FCK editor validation.

Declare a Custom Validator;

<asp:CustomValidator runat="server" ID="cvBody" SetFocusOnError="true" Display="dynamic" Text="The Body is required" ClientValidationFunction="ValidateContentText"></asp:CustomValidator>

Add this Javascript function to your page

function ValidateContentText(source,args)
{
var fckBody= FCKeditorAPI.GetInstance('<%=FCKeditor1.ClientID %>');
args.IsValid = fckBody.GetXHTML(true) != "";
}

Ref: “fck validation